Electro-hydraulic manifold assemblies having a plurality of solenoid operated valves disposed on a manifold block, each operable to control pressure from the inlet to a separate outlet, are used in many industries. Sensing ports are provided in each outlet with a pressure sensor sealed over the sensing port for providing a signal indicative of the sensed pressure. The pressure sensors are mounted on a lead frame and connected to conductive strips in the lead frame. The lead frame has slots therein, which permit the frame to be simultaneously electrically connected by bayonet connection to the terminals on each solenoid valve as the transducers are sealed over the sensing ports and the lead frame attached to the manifold block.
Manifolds of this type are employed for controlling pressure of hydraulic fluid in servo-actuators as, for example, clutch actuators in automatic speed-change power transmissions for motor vehicles where it is desired to control the speed change or shifting patterns of the transmission with an electronic controller. This arrangement has found widespread use in modern automatic vehicle transmissions because the electronic controller can receive in real time multiple inputs of vehicle operating parameters such as road speed, throttle position and engine RPM; and the electronic controller can be programmed to provide optimum shifting patterns based upon known engine power available, vehicle mass and the operating parameter inputs.
In providing a shifting pattern for controlling hydraulic fluid pressure to each of the transmission speed change clutch actuators for effecting the desired shifting, it has been found that providing pressure sensors at the outlet of each of the electrically operated valves can provide a clutch actuator pressure signal in real time, which is in actuality an analog of the force on the clutch that is in turn proportional to the torque transmitted by the clutch during engagement and disengagement. Such an arrangement provides an electrical signal proportional to torque transmitted for a particular gear set and thus provides real time closed loop control of the transmission shifting. This arrangement has been found desirable as an alternative to predetermined shifting algorithms for open loop shift control by the electronic controller.
Electrically connecting the plurality of pressure sensors to the solenoid operated valves in a transmission shift control module or manifold assembly in a manner, which is simple and easy to install in mass production and yet is sufficiently low in cost, gives rise to a need for a novel, low cost method for assembling and testing the hydraulic manifold. The assembly and testing of the hydraulic manifold includes providing at least one component to be assembled and tested from a component group that has at least one: electro-hydraulic proportional valve, electro-hydraulic “on/off” valve, sensor for providing at least one feedback signal, retention component, and optional microprocessor/control unit.